"Afghans are fighting a war against terrorists who are trained, advised, supported and instructed in our neighborhood," he asserted in a statement in a veiled reference to neighboring Pakistan.

The Afghan government has long accused Pakistan, particularly its military institutions, of covertly supporting the Taliban insurgency in Afghanistan, charges Islamabad rejects.

Twin bombings

The assault on the CARE charity came hours after a twin Taliban bombing near the Defense Ministry in the Afghan capital killed at least 30 people and wounded dozens more.

Officials and witnesses said a planted device was first detonated, prompting dozens of army and police officials to reach the site just before a Taliban suicide bomber wearing the uniform of Afghan security forces blew himself up.

The powerful explosion killed among others, top defense ministry and intelligence officials and police officers.

Afghanistan's Tolo TV reported that the ministry's senior commander, General Abdul Raziq, along with the intelligence chief for the capital city and a district police chief, were among those killed.

Kabul, Afghanistan

Taliban spokesman Zabihullah Mujahid says the insurgents were behind Monday's attack, claiming they killed around 60 people, mostly personnel of the Afghan security forces, although the insurgent group often issues inflated tolls for such attacks.

President Ashraf Ghani condemned the bloodshed, saying, "The enemies of Afghanistan have lost their ability to fight the security and defense forces of the country and thus attack highways, cities, mosques, schools and common people."

For its part, a Pakistan foreign ministry statement condemned the twin Taliban bombings in Kabul as a "brutal terrorist attack." It extended condolences to the government and the people of Afghanistan as well as to families who lost loved ones.

The United States also on Tuesday denounced the violence and offered condolences to the victims, saying these "horrendous attacks" reinforced the callous disregard the Taliban have for the innocent men, women and children of Afghanistan.

"We will stand strong with them and all our friends in Afghanistan as they strive to improve citizen safety and security and secure lasting peace in this nation," a U.S. embassy statement in Kabul quoted Ambassador P. Michael McKinley as saying.

Kunduz situation

The Kabul attack came hours after security forces retook control of a key district from the Taliban in the volatile northern province of Kunduz.

Afghan security forces prepare themselves during a battle with insurgents on the outskirts of Kunduz, Afghanistan, Aug. 21, 2016.

Area commanders say the insurgents were forced to retreat from Qala-i-Zal after the forces, backed by air support, staged an early morning assault on the district that the insurgents overran about a month ago.

The Taliban has stepped up its campaign of violence and battlefield attacks, inflicting heavy casualties on the security forces.

The commander of U.S. and NATO forces in Afghanistan, General John Nicholson, said last week that more than 900 Afghan soldiers and police personnel were killed in July alone.